The mercy seat made of pure gold was used as a cover over the ark containing the stone tablets inscribed with the Ten Commandments.
There are two mercy seats mentioned in the Bible.
One is the incorruptible sanctuary of the kingdom of heaven and the sanctuary built on the earth, which is a model of the sanctuary, which existed in the tabernacle in Exodus 25.
In English, it means a mercy seat, that is, a place where the law is covered with a ‘seat of grace’ to receive the grace of receiving the ransom for sins and avoiding death.
[Related Verse]
Exodus 25:16
I will put the Testimony that I will give you in the ark.
Exodus 25:17
Make a mercy seat of pure gold, two and a half cubits long and one and a half cubits wide.
Exodus 25:18
Make two cherubs of gold, struck at the two ends of the mercy seat.
Exodus 25:19
One cherub at one end and one cherub at the other end, at the two ends of the mercy seat, with the mercy seat.
Exodus 25:20
The cherubim spread their wings high, covered the mercy seat with their wings, and turned their faces toward each other toward the mercy seat.
Exodus 25:21
Place the mercy seat on top of the ark, and put the Testimony, which I will give you, into the ark.
Exodus 25:22
There I will meet with you, and from above the mercy seat, from between the two cherubim that are above the ark of the testimony, I will tell you everything I will command you for the children of Israel.